- 1. The Circle and Its Parts
Identify and distinguish between the centre, radius, diameter, chord, circumference, arc, sector, and segment of a circle.
- 2. Circumference: Measuring Around the Full Circle
Calculate the circumference of a circle given its radius or diameter, and work backwards to find radius or diameter given the circumference.
- 3. Arc Length: The Fraction Principle
Understand that an arc is a proportional fraction of the full circumference, and calculate the length of minor and major arcs.
- 4. Perimeter of a Sector
Calculate the total perimeter of a sector by adding the arc length to twice the radius, and find the arc length given the perimeter.
- 5. Area of a Sector
Calculate the area of a sector using the fraction principle and distinguish between area and perimeter formulas.
- 6. Reverse Problems I: Finding the Angle
Rearrange the arc length and sector area formulas to find the central angle, and extract arc length from perimeter before finding the angle.
- 7. Reverse Problems II: Finding the Radius
Rearrange the arc length and sector area formulas to find the radius, and use perfect squares to check for accuracy.
- 8. Area of a Triangle Inside a Circle
Calculate the area of a triangle formed by two radii and a chord, and apply the theorem that the angle in a semicircle is 90 degrees.
- 9. WAEC/JAMB Consolidation
Recall and apply all major circle formulas to solve composite multi-part examination problems.
